Why would I use the "Film Emulation" feature?
The key advantage is that it works real-time in the view-port.
Of course all color manipulation could be done once the file is saved.

However having this apply to previews while you're setting up your scene means you can setup a a rough grade, and then build the lighting off of that. This allows you to get a really good idea of where you need more detail in the render, and also gives you a more accurate representation of how your lighting will look once everything is color graded.

The look settings can also help give a rough grade without much work. There's also the plus that they're based off of real life film types.

There's also a log setting. According to the manual, this is intended more as a way to trouble shoot the image, but it can also be used to get a nice flat image for use when grading.